Katie Holmes is currently bundling
up with the rest of frigid New York City, but just because she’s keeping her
body under wraps for now doesn’t mean she isn’t working hard every day to keep
it beach-ready. In fact, when Holmes bared her winter bikini body a few weeks
ago in Miami, the results were jaw-dropping. Only RadarOnline.com has all the
details about how the 35-year-old single mom has managed to sculpt her hottest
body ever in the middle of
winter.

“Katie is feeling great lately because of her intense workouts,” a source
reveals.

Even though the streets of Manhattan are covered with ice and snow, the
former marathoner has “been running a lot on the treadmill,” the source
confirms. To keep things fresh, she’ll occasionally pop into a SoulCycle
spinning class or text a friend for a workout. The source says, “She has a few
regular workout buddies, and they’ll go to the gym together when the kids are at
school.”

But since mommy-daughter time with Suri or business meetings can
sometimes take precedence over gym time, the source says Holmes is sticking to a
strict diet all winter.

“Katie is doing a mainly paleo diet,” the source explains. Also known as the
“Caveman Diet,” the plan features lots of “fish, other lean proteins, and
vegetables,” says the source. “Katie says she always craves comfort food and
carbs in the winter, but she’s trying to stick to it.”

That doesn’t mean there isn’t room for a few sweet indulgences, however. “She
keeps an eye on her overall calorie count too, so if she’s been doing well all
day she’ll treat herself to dessert,” the source explains.